More plant species responding to global warming than previously thought

May 22, 2012
By Kim McDonald

Credit: Elizabeth Wolkovich

(Phys.org) -- Far more wild plant species may be responding to global warming than previous large-scale estimates have suggested.

Thats the conclusion of a team of scientists, which included a UC San Diego biologist, that found that many plant species, which appear to not be affected by warmer spring temperatures, are in fact responding as much to warmer winters. The scientists detailed their findings in this weeks early online publication of the journal Proceedings of the National Academy of Sciences.

For years, scientists have accepted that certain species are flowering earlier each year due to changes in climatic conditions, but many speciesvarying around 30 percent, depending upon the regionappeared not to be affected. These species had been assumed to be stableunresponsive to global warming and thus outside of concern for how they will change with increasing rates of climate change.

But the team of researchers, led by Benjamin Cook, a climate modeler at the NASA Goddard Institute for Space Studies and Columbia Universitys Lamont-Doherty Earth Observatory, found that the apparently stable species are, in fact, unquestionably feeling the effects of rising temperatures throughout the year.

]Based on what we know from agriculture and plant physiology, we expect our results would be broadly applicable to many temperate regions where species are dormant in usually cold winters, said Elizabeth Wolkovich, who co-authored the study while a postdoctoral fellow in biology at UC San Diego. We expect that our results extend to many temperate habitats in Southern California, but we need more data for the best estimates and predictions of what future California springs will look like.

Credit: Elizabeth Wolkovich

The study was part of efforts by a multi-national working group team, carried out at the National Center for Ecological Analysis & Synthesis, to better predict how plant leafing and flowering has and will continue to change with warming. The research teamwhich included Camille Parmesan of Plymouth University's Marine Institute in the UKused data collected by citizen scientists in England and the United States to show that many species (about 10 to 18 percent of species studied) advance their flowering with warmer springs, as have been previously found, but also delay warming with warmer wintersa so-called chilling requirement.

Many of the species that have not appeared to be altering their spring timing in recent years need cold winters to tell them when to become dormant and when to wake up in spring. With winters getting warmer, these species appear to be waiting for their cold cue, which can end up delaying their normal responses to the arrival of spring. The end result is species that show no change, or even a delay, in spring budding, leafing or blooming, in apparent contradiction with warming spring temperatures.

This new study resolves that contradiction for many species, indicating about two-thirds of stable species are, in fact, sensitive to warmer springs, but even more so to warmer winters, with the end result being a confusion in timing of leafing, budding or blooming.

Weve known about the need for cold winters to meet chilling requirements for many well-studied crop and lab species for a long time, said Cook. But this is the first study to estimate how prevalent chilling requirements may be in wild plant communities and  further, to link to how plants change with global warming.

The scientists say further research is needed to figure out how such species will respond with continuing warmer winters and springs.

The little data we have from other research suggests that species that do not meet their chilling requirementswhich is a highly possible outcome of global warmingmay flower erratically, that is far too early, or late or not at all, said Wolkovich, who is now at the University of British Columbia. Right now these species appear to have not changed much over time, but all our understanding of basic plant physiology suggests they will shift their flowering dramatically in the future.

The key for future research will be understanding how we can predict what species and regions are most at risk of radical changes in their flowering due to warmer winters, she added. For that, we need far more data, especially from areas with few datatemperate regions throughout the US West, but especially in Southern California are some of the areas where we have almost no data on when species leaf and flower and how it has changed in recent decades. People can help by joining an observer network such as the National Phenology Network (www.usanpn.org/participate/observe) or asking about opportunities at their local botanical clubs or natural history museums.

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18 comments

I wouldn't call myself a global warming denialist. However, I always found it funny how alarmist climate scientists would become about species preservation given global warming when they also believe in evolution, something I also believe in. Physical destruction of habitat? Sure that's a threat that is too sudden to adapt to. Chemical toxins spilling everywhere? Check. But a few degrees increase in temperature over a century? What happened to mutation and selection? Did that just go out the window? While the planet may be warming, and may be warming due to us, this whole attitude of 'the sky is falling' with regards to biodiversity is just bullf*ck

50% of climate change science is about science. Actual study of changing climate. The other half is politics. It is an attack on the individual rights of people to make choices in their lives, under the justification that it is good for everyone. All the while, the legal changes they implement ignore the reality of economies (can we afford it) and the effect on the poor (can they afford it). Look at what Japan has done in response to the extremists. They are now emitting 30% MORE CO2 with the shutdown of their nuclear plants. Instead of following a methodical plan to integrate alternative energy sources to replace coal, then nuclear, they just off their noses to spite their faces. Now they have rolling power blackouts more often than before AND the air quality will be worse.

A major food problem of increasing CO2 is the equilibrium shift of some plants to increase means for protection & that results in cyanide, this applies to Cassava (a tuber used for food in Africa) & Clover a livestock feed crop & perhaps others.

Already people in Africa suffering from paralysis from increased levels of HCN in Casava. Although not enough to kill outright does incrementally lead to lower limb paralysis and if continued consumption leads to death. Unfortunately the condition appears as if its infectious polio.

Suffice it to say, government agencies are monitoring other livestock food crops in Europe and USA.

For non plant biologists, an analogy:-

You work and get food, some is stored some is consumed. If the key input for food is more plentiful, you store more but also start taking (more) steps to protect what you have and that means adding compounds that disassociate into Hydro-cyanic gas (HCN) when food is stolen. Ostensibly as warning to predators...

To some, the apparent improved growth by the plants due to global CO2 level increases (from fossil fuel) is a good thing. It is a good thing too only if we could stabilize CO2 levels to the current levels of around 400ppm. Unfortunately for our planet, that isn't going to happen. CO2 levels will climb faster and average temperatures will increase proportionally until we are a good 5 to 10 degree C higher than 1970 normals turning everything into a waist land.

In higher level organisms n and r are small and hence evolutionary rates are low.

In the case of single celled organisms, n and r are very high in comparison so the evolutionary rate is high.

Bacteria have nothing to fear from global warming. Elephants, polar bears, and people will not be evolving fast enough to cope with large temperature changes occurring over periods that are on the same order of magnitude as their reproduction rate.

"What happened to mutation and selection? Did that just go out the window?" - foofighter

Shameful how few Americans understand how Evoluition works. I blame the Republican attack on science.

"The other half is politics" I noticed that too. It is quite an interesting pattern. Yet another scientific article is published - strengthening our understanding of the climate - and the changes happening in our world - and then the comments sections start - and off we go with the politics. It is the socialists - or the evil scientists all lying to keep their funding - or Al Gore - etc etc. Interesting pattern I think.

And the blind man said the elephant is like a tree, no, like the side of a building, no. like a rope.... and he was right. Change is, change was, change will always be. Cast not the first stone! Perhaps we are all right. Do what we can, but don't cut off your nose.

How do they know that? Corelation alone cannot prove causation. On the other hand, the environment is complex. There could be another cause. For example, it is known that CO2 affects plants development. CO2 quantity increased, too. How one would know it's 'warming' and not CO2? They already felt in this trap with tree rings, assuming that growth is driven by temperature alone, ignoring CO2 variations or humidity.

Good bit of philosophizing and life is all about change. What needs to be pointed out very clearly is that rapid change in fundamental environmental conditions will almost certainly lead to catastrophe. Experience proves the teacher (ie; the environment has gone through rapid change, and for some life it wasn't pleasant).

Bacteria have nothing to fear from global warming. Elephants, polar bears, and people will not be evolving fast enough to cope with large temperature changes occurring over periods that are on the same order of magnitude as their reproduction rate.

Vendicar D. A bit of a digression but a precise and interesting illustration of the potential effect of differences in reproduction rates is given by insect parasites of trees.

An example I have studied is with Leptocnaria Reducta a moth parasite of Melia Azedarach, the tree known as 'Cape Lilac' in Western Australia', 'White Cedar' in the eastern states, and 'Chinaberry' in USA. In the South West of WA our warm temperate [often f****ng hot] climate the beasties proliferate each year going through about four [4!] life cyles whereas the trees about 3 years to start flowering. ..cont ..

Caterpillars ...cont: The result of this is that the caterpillars at each stage of growth exactly match features of the bark at that particular scale and the tree's defensive poison becomes a noxious defense for the parasites.

In WA where I live the caterpillars have only been common for about a couple of decades and have no significant natural predators. The trees were introduced to our South West many decades ago and are now essentially a benign but potentially useful weed. I have a webpage which shows how annoying and bizarre can be the average person's experience of these horrid little buggers:http://www .amnet .net .au/~mpeaty/pests1 .html[remove the spaces before copying the URL, if interested].

note: infected trees get all their leaves eaten off by the third and/or fourth generations each year, but they survive.

Yes I have them too in Mt Hawthorn but, I have experimented with ways to dissuade recurrence & cottoned on to detergent bubbles for the last couple of years though timing has to be good, as I am so often distracted on the net, missed out this time. Interesting about molasses. Tumeric's good slowing ants, wont kill, which is fine as ants attack termites.

Caffeine could also be used as it is a natural means to dissuade insects & if strong enough, a pesticide, so no ants in the lower bowels then ;-)

For caterpillars, edible, doubt it ugh !I found water at ~60 C & organic biodegradable detergent such as "Earth Choice" but around 50mls per litre was best. I dont want to dissuade ants so no tumeric but will add molasses :-)

I put spring onions in water so I can regrow them 3 times but get nematodes & mozzie larvae, yuk...

I don't understand how climate scientists can acknowledge that the warming has stalled and claim that this is a temporary anomaly and then non-climate scientists can "discover" all these recent effects of climate change (ignoring the real climatologists admission of a lack of warming) and say skeptics are unscientific for not accepting what climatologists say as fact. Who is really "denying" climate scientists, the skeptics or the ecologists?

Sean W, who says 'real climatologists' admit a lack of warming? Just yesterday/Saturday I was listening to the ABC [Aust.]Radio National 'Science Show' program and a researcher was reporting how they have been running and re running climate modelling software, about 3000 times while tweaking the parameters to home in on settings which cause the software to emulate data from tree rings and other sources for most of the previous millennium. They have been successful in this; their software will successfully mimic the temperature variations in Europe since about the 13 Century, _but_ it will not replicate the temperatures measured since the 1950s _unless_ anthropogenic green house gas emissions are included.

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